Two colors (positive and negative) chart for indicator in separated windows

[Cong Hoa Cuong Nguyen]

Hello, I am trying to learn mql5, so basically a newbie in this language.

I am trying to build a simple (and probably useless) indicator that would show a positive (green) bar when close price go up compared to the previous bar, and a negative (red) bar when priced go down.

I tried to look into some code from the average speed indicator and it helps me to build a positive (green) bar. However, I could not figure out how to add another color and negative measurement.

Any help?

Thank you. 

Edit: Something like this.

This is what I have now

#property indicator_separate_window
#property indicator_minimum 0
#property indicator_buffers 1
#property indicator_plots   1
//--- plot Output
#property indicator_label1  "Output"
#property indicator_type1   DRAW_HISTOGRAM
#property indicator_color1  clrGreen //How do I add the property indicator_color2 for negative number?
#property indicator_style1  STYLE_SOLID
#property indicator_width1  2